On the electronic structure of TiNx

Abstract
The electronic structure of substoichiometric TiNx is studied in terms of the KKR GF and KKR CPA methods. In accordance with recent XPS studies the cases of both a single vacancy and concentrated vacancies show peaks in the vicinity of the minimum in the density of states of the stoichiometric compound. The nature of the 'vacancy sub-band' is analysed in detail in terms of the resonance condition for virtual bound states. The Fermi energy for TiNx, x=0.75, is lower than in the stoichiometric case, the density of states at EF being about 10% higher in the non-stoichiometric system than in the pure system. It is argued that the results obtained are also characteristic of other substoichiometric refractory carbides and nitrides.